Primitive cells help blind mice see

Primitive retinal cells, that were previously thought to have no role in image formation, can help blind mice see.

These photosensitive cells, known as ipRGCs, respond to light so that we know when to sleep, for instance. But they were not thought to play any role in seeing patterns or shapes.

The cells were studied in mice without the rod or cone cells which are normally required to form images. The blind mice were divided into two groups – one with the ipRGCs and one without. In vision tests, the mice with the photosensitive cells were able to follow the movements of a rotating drum, which assesses their capability of tracking moving objects. Another test involved a ‘Y’ shaped maze from which mice could leave after selecting a certain visual pattern.

Mice that lacked the ipRGCs as well as rod and cone cells were unable to complete the tasks. But with the ipRGC cells they were able to see shapes and patterns. These results suggested that the special eye cells can help clarity of vision. Perhaps in the past ipRGCs aided vision, but their function has since been overtaken by rod and cone cells.

Researchers hope this discovery could aid future treatments for people with severe visual impairment. People with poor vision might be trained to use their ipRGCs again to perform simple tasks that require some clarity of vision.